This invention relates to gas bearings for rapidly rotating parts on textile machines such as spinning and twisting machines, and, in particular, to gas bearings for spinning rotors, spinning rings and spinning spindles.
Many gas bearings having thin foils as bearing elements have in the past been ill suited to support axial loads. For optimum stability, such gas bearings often require at least one radial foil bearing to support radial loads and two axial bearings to support axial loads. Here each axial bearing supports axial loads in one direction, one axial bearing serving to absorb the weight of the spinning rotor during standstill and during startup.
During the spinning operation when a textile machine is operating at speed the moving thread may often exert axial forces on the rotor in an upward direction, which forces may exceed the weight of the rotor by a considerable amount. In this case, a second axial bearing surface is necessary to bear these upward forces. The carrying capacity of this second axial bearing surface is, however, limited by the oblique position of the rotor, i.e., the axial rotor surface and the axial stator surface at times are not oriented parallel to one another. This oblique positioning of the rotor with respect to the axial stator is often caused by dynamic imbalance of the ring rotor even in the case of an optimally balanced rotor. With conventional gas bearings of the prior art this second axial bearing could be eliminated only if the weight of the rotor could be made greater than the upward-acting axial forces of the thread; in many cases, however, it is not practical to make the rotor so heavy.